[Form] TransformationFailedException with JSON submitted data

[asentner]

Symfony version(s) affected: 3.4.24 / 4.2.5

Description
TransformationFailedException thrown when JSON is submitted through HiddenType field. I have one form that is passing a JSON which is a canvas map of a captured signature.

This commit creates the breaking change for us:

symfony/form@4f7d286#diff-9c65c1fe9e9fce8398f48544b0bbf2a5

Specifically this block of code:

} elseif (\is_array($submittedData) && !$this->config->getCompound() && !$this->config->hasOption('multiple')) {
    $submittedData = null;
    $this->transformationFailure = new TransformationFailedException('Submitted data was expected to be text or number, array given.');
}

This runs before a transformer can clean the data and a mapper does not seem to be a good fit for this.

How to reproduce
Submit JSON through a HiddenType form field

Possible Solution
Check for an additional form option scalar = false or something along those lines.

Example JSON:

[  
   {  
      "lx":132,
      "ly":67,
      "mx":132,
      "my":66
   },
   {  
      "lx":118,
      "ly":27,
      "mx":118,
      "my":26
   },
   {  
      "lx":144,
      "ly":19,
      "mx":144,
      "my":18
   }
]

This can get quite large depending on the size of the complexity of the signature. Transformers and mappers seem to run after this exception is thrown.

Thoughts?

[HeahDude]

Hello @asentner, thank you for opening this issue.

I don’t really understand the necessary steps to reproduce. It seems to me that submitting some json means submitting a string that should not break a hidden field submission. How do you handle transformation exactly?

[dmaicher]

This seems to be the same issue as reported in

#29809
#29841

?

[HeahDude]

Yes we should close here.

[fabpot]

Closing as a duplicate then.

[Pasuvan]

Hi @ALL, @asentner
Did you solve the above issue, Can you explain how to you solved? Because I have the same issue.
Please help me.

[lushc]

The solution to this issue can be found here: #29809 (comment)

Specifically, you need to create & use a new form type that allows you to submit this kind of unstructured data: https://github.com/sulu/SuluArticleBundle/blob/c0ed0b34b2903d517f555811276d0ad7f598497e/Document/Form/UnstructuredType.php#L12-L32